JP2020083093A - Control device of vehicle - Google Patents

Abstract

To suppress drivability from becoming worse caused by frequent repetition of gear change in a stepped automatic transmission.SOLUTION: A control device of a vehicle having a stepped automatic transmission 3 includes: a slope acquisition part 61 for acquiring a slope of a road on which the vehicle is planned to travel in the future; a driving force calculation part 62 for calculating maximum driving force when a gear stage of the automatic transmission is a current gear stage; a future change estimation part 63 for estimating change in the future speed or acceleration speed of the vehicle on the basis of the slope of the road and the maximum driving force; and a shift control part 64 for controlling a gear stage of the automatic transmission. The shift control part inhibits change in the gear stage when the change speed of the future speed or acceleration speed of the vehicle is within a reference change speed range in which an occupant does not notice change in the speed or acceleration speed, and permits change in the gear stage when the change speed of the future speed or acceleration speed of the vehicle is out of the reference change speed range.SELECTED DRAWING: Figure 7

Description

The present invention relates to a vehicle control device.

The slope angle of the road on which the vehicle is traveling is detected, and the slope angle at which the vehicle can climb is calculated based on the output torque of the engine, the total gear ratio, and the loaded weight of the vehicle. There is known a vehicle control device that notifies that the vehicle cannot run uphill on the road when the angle is smaller than the gradient angle (for example, Patent Document 1).

JP, 2017-77765, A

By the way, in a stepped automatic transmission of a vehicle, the gear is set based on the operating state of the vehicle such as the accelerator pedal depression amount or the vehicle speed. Therefore, when the amount of depression of the accelerator pedal is constant and the vehicle accelerates and the speed of the vehicle increases, the automatic transmission automatically shifts up. On the other hand, when the vehicle is traveling on an uphill and the speed of the vehicle decreases, the automatic transmission automatically shifts down.

For this reason, when the vehicle is traveling on a road with many irregularities, the speed of the vehicle frequently increases and decreases, and as a result, upshifting and downshifting are frequently performed in the automatic transmission. If the shift up and shift down are frequently repeated in this manner, drivability is deteriorated.

In view of the above problem, an object of the present disclosure is to suppress deterioration of drivability due to frequent upshifts and downshifts in a stepped automatic transmission.

The summary of the present disclosure is as follows.

(1) A vehicle control device including a stepped automatic transmission, wherein a gradient acquisition unit that acquires a gradient of a road on which the vehicle is expected to travel in the future; Based on the maximum driving force calculated by the driving force calculation unit, the driving force calculation unit for calculating the maximum driving force when, and the gradient of the road and the driving force calculation unit, the future of the maximum driving force A future change estimation unit that estimates a change in vehicle speed or acceleration, and a shift control unit that controls a gear stage of the automatic transmission, wherein the shift control unit is the maximum drive estimated by the future change estimation unit. When the speed of change in the speed or acceleration of the future vehicle at the time of force is within the reference change speed range in which the passenger does not notice the change in speed or acceleration, the change of the gear is prohibited, and the future change estimating unit A control device for a vehicle, which permits a change of the gear when the change speed of the future speed or acceleration of the vehicle at the estimated maximum driving force is out of the reference change speed range.

(2) An output torque control unit that controls the output torque of the internal combustion engine is further provided, and the driving force calculation unit is configured such that the gear stage of the automatic transmission is the current gear stage and the output torque of the internal combustion engine is the present gear stage. Current driving force when it is the output torque of, the future change estimating unit, based on the current driving force estimated by the driving force estimating unit and the road gradient acquired by the gradient acquiring unit, A future change in vehicle speed or acceleration when the driving force is assumed to continue is also estimated, and the output torque control unit determines the future when the current driving force estimated by the future change estimation unit is assumed to continue. The output torque is controlled so that the change speed falls within the minimum change speed range when the change speed of the vehicle speed or acceleration is outside the minimum change speed range narrower than the reference change speed range. The vehicle control device described.

(3) The vehicle further comprises a communication device capable of communicating with another vehicle different from the vehicle, and the gradient acquisition unit is a vehicle that is traveling in front of the vehicle via the communication device. The control device for a vehicle according to claim 1, which acquires a gradient of a road on which the vehicle is to travel.

According to the present disclosure, it is possible to suppress deterioration of drivability due to frequent repetition of upshift and downshift in a stepped automatic transmission.

FIG. 1 is a diagram schematically showing a configuration of a vehicle equipped with a control device according to the first embodiment. FIG. 2 is a configuration diagram schematically showing the control device. FIG. 3 is a functional block diagram of the ECU related to vehicle control processing. FIG. 4 is a diagram showing the relationship between the vehicle speed (vehicle speed), the depression amount of the accelerator pedal (accelerator opening), and the gear position. FIG. 5 is a time chart showing changes in vehicle speed and gear speeds when the vehicle is traveling on a road where the gradient is changing. FIG. 6 is a time chart showing changes in vehicle speed, jerk, and gear speeds when the vehicle is traveling on a road having a changing gradient. FIG. 7 is a flowchart showing a shift determination process for determining whether or not a shift should be performed. FIG. 8 is a flowchart showing a shift determination process for determining whether or not a shift should be performed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in the following description, the same components are designated by the same reference numerals.

<First embodiment>
≪Vehicle composition≫
First, the configuration of the vehicle 1 will be described with reference to FIG. FIG. 1 is a diagram schematically showing a configuration of a vehicle 1 equipped with a control device according to the first embodiment. As shown in FIG. 1, the vehicle 1 includes an internal combustion engine 2, a stepped automatic transmission 3, a differential gear 4, and wheels 5.

The internal combustion engine 2 is a prime mover that burns a fuel such as gasoline or light oil inside the engine to convert the thermal energy of the combustion gas into mechanical energy. The output of the internal combustion engine 2 is controlled by adjusting the amounts of fuel and air supplied to the internal combustion engine 2.

The automatic transmission 3 is a power transmission device that transmits the power output from the internal combustion engine 2 by changing the torque and the rotation speed. The automatic transmission 3 is connected to a crankshaft (not shown) of the internal combustion engine 2 via a flywheel or the like, and power is input from the internal combustion engine 2. On the other hand, the automatic transmission 3 is connected to the differential gear 4 via the propeller shaft 6 and outputs power to the differential gear 4.

The automatic transmission 3 can transmit the power output from the internal combustion engine 2 at a plurality of different gear ratios. Here, the gear ratio means the ratio of the input side rotation speed to the output side rotation speed. In the automatic transmission 3, the gear ratio is automatically switched according to the operating state of the internal combustion engine.

In this embodiment, the automatic transmission 3 has four gear stages, and therefore can transmit power at four different gear ratios. In the first to fourth gears, the gear ratio is highest in the first gear and lowest in the fourth gear. In the present embodiment, the automatic transmission 3 has four gears, but the number of gears may be any value as long as the automatic transmission 3 has gears.

The differential gear 4 is used to evenly distribute the power transmitted from the automatic transmission 3 to the left and right wheels 5 while absorbing the rotational speed difference between the left and right wheels 5. The differential gear 4 transmits power to the left and right wheels 5 via the drive shaft 7.

≪Control device≫
Next, the configuration of the control device 10 of the vehicle 1 will be described with reference to FIG. FIG. 2 is a configuration diagram schematically showing the control device 10. As shown in FIG. 2, the control device 10 includes an ECU 11. The ECU 11 controls the internal combustion engine 2 and the automatic transmission 3.

The ECU 11 has an in-vehicle communication interface 12, a memory 13, and a processor 14. The in-vehicle communication interface 12 and the memory 13 are connected to the processor 14 via signal lines.

The in-vehicle communication interface 12 has an interface circuit for connecting the ECU 3 to an in-vehicle network 15 that complies with standards such as CAN (Controller Area Network). That is, the in-vehicle communication interface 12 is connected to various actuators and various sensors described later via the in-vehicle network 15. Then, the in-vehicle communication interface 12 receives output data from various sensors and transmits the received output data to the processor 14. Further, the in-vehicle communication interface 12 inputs the output signal transmitted from the processor 14 to various actuators.

The memory 13 has, for example, a volatile semiconductor memory and a non-volatile semiconductor memory. The memory 13 stores various data used when various processes are executed by the processor 14. For example, the memory 13 stores output data, map information, etc. received from various sensors. The memory 13 also stores a computer program for the processor 14 to execute various processes.

The processor 14 has one or more CPUs (Central Processing Units) and their peripheral circuits. The processor 14 may further include a GPU (Graphics Processing Unit). While the ignition switch of the vehicle 1 is on, the processor 14 executes a shift determination process described below at regular time intervals and controls the actuator of the automatic transmission 3 based on the result of the shift determination process.

In the present embodiment, the control device 10 further includes an engine actuator 21, a transmission actuator 31, an accelerator sensor 41, a vehicle speed sensor 42, a torque sensor 43, a weight sensor 44, an external communication device 51, and a GPS receiver 52. The actuator, the sensor, the vehicle exterior communication device 51, and the GPS receiver 52 are connected to the vehicle interior communication interface 12 of the ECU 11 via the vehicle interior network 15.

The engine actuator 21 is various actuators for controlling the internal combustion engine 2. The engine actuator 21 is, for example, a fuel supply device that supplies fuel to the combustion chamber of the internal combustion engine 2, an opening control device that controls the opening of a throttle valve provided in the engine intake passage, and a mixing chamber inside the combustion chamber of the internal combustion engine 2. Includes a spark plug to ignite the air. Therefore, the engine actuator 21 can adjust the output torque of the internal combustion engine 2.

The transmission actuator 31 includes a solenoid that drives a brake mechanism and a clutch mechanism that control the rotation of a ring gear, a pinion gear, and a sun gear provided in the automatic transmission 3. Therefore, the transmission actuator 31 can change the gear stage of the automatic transmission 3.

The accelerator sensor 41 is attached to the accelerator pedal and detects the depression amount of the accelerator pedal. The vehicle speed sensor 42 is attached to, for example, the wheel 5 or the drive shaft 7, and detects the speed of the vehicle 1. The torque sensor 43 is attached to, for example, the output shaft (crankshaft or propeller shaft) of the internal combustion engine 2 or the automatic transmission 3 and detects the output torque of the internal combustion engine 2 or the automatic transmission 3. The weight sensor 44 is attached to, for example, the suspension of the vehicle 1 and detects the weight of the vehicle 1. The outputs of these sensors are input to the ECU 11 via the in-vehicle network 15.

The external communication device 51 is a device that can wirelessly communicate with a server outside the vehicle or another vehicle. Standards used in wireless communication include long-term evolution (LTE) established by 3GPP, wireless LAN (IEEE 802.11a/b/g/n/ac), Mobile WiMAX (IEEE 802.16e), iBurst and WAVE. Various communication standards such as (IEEE 802.20) and DSRC (Dedicated Area Communication) can be used. The vehicle exterior communication device 51 transmits/receives a signal to/from the ECU 11 via the vehicle interior network 15.

The GPS receiver 52 is a device for receiving signals from three or more GPS satellites and detecting the current position of the vehicle 1 (for example, the latitude and longitude of the vehicle 1). The GPS receiver 52 transmits the detected current position information of the vehicle 1 to the ECU 11.

<<Process in ECU>>
FIG. 3 is a functional block diagram of the ECU 3 relating to vehicle control processing. The ECU 3 includes a gradient acquisition unit 61, a driving force calculation unit 62, a future change estimation unit 63, a shift control unit 64, and an output torque control unit 65. These functional blocks of the ECU 3 are, for example, functional modules implemented by a computer program operating on the processor 14. Note that these functional blocks may be dedicated arithmetic circuits provided in the processor 14.

The gradient acquisition unit 61 acquires the gradient of the road on which the vehicle 1 will travel in the future. In particular, the gradient acquisition unit 61 acquires the gradient of the road scheduled to travel within the latest predetermined time among the roads in the travel route planned for the vehicle 1 to travel in the future.

The gradient acquisition unit 61 acquires the gradient of the road, for example, based on the current position information of the vehicle 1 transmitted from the GPS receiver 52 and the map information stored in the memory 13. In this case, the map information includes gradient information of each road. The gradient acquisition unit 61, based on the current position information transmitted from the GPS receiver 52 and the preset traveling route, is a road on which the vehicle 1 will travel in the future (specifically, for example, within the next 10 seconds). A road that is planned to travel or a road that is within 1 km from the current position where mixed travel is planned) is specified. After that, the gradient acquisition unit 61 acquires the gradient of the road scheduled to travel in the future from the map information stored in the memory 13.

In this case, the ECU 3 may be configured to update the map information stored in the memory 13 via the vehicle exterior communication device 51 at any timing. Specifically, when the map information of the external server (not shown) is updated, the updated map information is transmitted from the server to the communication device 51 outside the vehicle, and the map information stored in the memory 13 is transmitted. It is updated with octopus map information.

The update of the map information of the external server may be automatically performed by the gradient information transmitted from the vehicle traveling on the target road. In this case, the vehicle traveling on the target road calculates the gradient θ of the road using, for example, the following formula (1).
θ=arcsin[(Fd−M·a−F(A·v ² +B·v+C))/M·g] (1)
Here, Fd is the driving force output by the vehicle, M is the total weight of the vehicle, a is the acceleration of the vehicle, F is the running resistance assuming that the gradient is 0, v is the speed of the vehicle, and g is gravity. Represents acceleration respectively. A, B and C are constants calculated or experimentally calculated.

The driving force Fd is calculated, for example, based on the accelerator pedal depression amount, the gear stage of the automatic transmission 3, and the like. The total weight M of the vehicle is calculated, for example, based on the weight sensor 44 and the like provided on the suspension of the vehicle. The acceleration a of the vehicle is calculated, for example, based on the output of the vehicle speed sensor 42. In addition, the running resistance F is calculated in advance experimentally or by calculation for each vehicle type.

For the vehicle that has traveled on the target road, the ECU 3 calculates the gradient of the road based on the driving force Fd, the total weight M of the vehicle, the acceleration a of the vehicle, and the running resistance F using the above equation (1). .. After that, the vehicle transmits the slope information of the road on which the vehicle has traveled to the server together with the position information. The server updates the map information based on the gradient information and the position information transmitted from the vehicles traveling in this way.

In the present embodiment, the gradient information of each road calculated by each vehicle is transmitted to the server, the map information updated based on the gradient information is transmitted to each vehicle, and the map information is transmitted to each vehicle. Based on this, the slope of the road that is planned to travel in the future is acquired. However, each vehicle may be configured to directly receive the gradient information of the road on which the vehicle 1 is to travel in the future, together with the position information, from another vehicle around the vehicle that travels in front of the vehicle 1. In this case, the gradient acquisition unit 61 is planned to travel in the future based on the road information on which the vehicle 1 is to travel in the future and the map information stored in the memory 13 and the gradient information and position information received from another vehicle. To get the slope of the road.

The driving force calculation unit 62 calculates the driving force of the vehicle 1 when the gear stage of the automatic transmission 3 is the current gear stage. The driving force calculation unit 62 particularly estimates the maximum driving force when the gear stage of the automatic transmission 3 is the current gear stage. In addition, the driving force calculation unit 62 calculates the current driving force when the gear stage of the automatic transmission is the current gear stage and the output torque of the internal combustion engine 2 is the present output torque.

The driving force of the vehicle 1 when the amount of depression of the accelerator pedal is maximum (that is, when the output of the internal combustion engine 2 is maximum) changes according to the gear position of the automatic transmission 3 and the speed of the vehicle 1. The maximum driving force means the largest driving force that the vehicle 1 can output when the speed of the vehicle 1 is changed in each gear of the automatic transmission 3. The relationship between each gear and the maximum driving force is preliminarily calculated experimentally or by calculation and stored in the memory 13, and the driving force calculating unit 62 causes the memory 13 to calculate based on the current gear of the automatic transmission 3. The maximum driving force is calculated using the relationship stored in.

On the other hand, the driving force of the vehicle 1 changes depending on the gear position of the automatic transmission 3 and the speed of the vehicle 1 as well as the depression amount of the accelerator pedal. In the present embodiment, the relationship between each gear, the driving force, and the depression amount of the accelerator pedal is preliminarily calculated experimentally or by calculation and stored in the memory 13. The driving force calculation unit 62 uses the relationship stored in the memory 13 based on the depression amount of the accelerator pedal output by the accelerator sensor 41 and the current gear position of the automatic transmission 3 to determine the current accelerator pedal position. The driving force (current driving force) when the depression amount is calculated is calculated.

The future change estimation unit 63, based on the road gradient acquired by the gradient acquisition unit 61 and the maximum driving force calculated by the driving force calculation unit 62, determines the future vehicle 1 when the maximum driving force continues. The change in acceleration a is estimated. The acceleration a of the vehicle 1 at time t is calculated, for example, by the following equation (2).
a=[Fdm−F(A·v ² +B·v+C)−M·g·sin θ]/M (2)
Here, Fdm represents the maximum driving force output by the vehicle 1, and the value calculated by the driving force calculation unit 62 is substituted. Further, θ represents the road gradient, and the value acquired by the gradient acquisition unit 61 is substituted.

In particular, in the present embodiment, the current acceleration a is calculated by the above equation (2) based on the current speed of the vehicle 1 detected by the vehicle speed sensor 42. Then, the speed of the vehicle 1 after a minute time Δt seconds is calculated based on the current acceleration a calculated in this way, and the vehicle 1 travels after a minute time Δt seconds based on the current speed. The existing road (position) is calculated. Then, the gradient of the road on which the vehicle 1 is traveling is calculated after Δt seconds from the gradient of the road acquired by the gradient acquisition unit 61, and based on the calculated gradient of the road and the speed after Δt seconds, The acceleration a after Δt seconds is calculated. By repeating such an operation, a change in the acceleration of the vehicle 1 from the present to a predetermined time (for example, 10 seconds) later is estimated.

In addition, in the present embodiment, the future change estimation unit 63 estimates the change in jerk, which is the change speed of acceleration. Specifically, the jerk at time t is calculated as the difference between the acceleration a(t) at time t and the acceleration a(t+1) at time t+1.

The shift control unit 64 controls the gear stage of the automatic transmission 3. In the present embodiment, the shift control unit 64 is basically based on the current speed of the vehicle 1 detected by the vehicle speed sensor 42 and the accelerator pedal depression amount (accelerator opening degree) detected by the accelerator sensor 41. Set the gear.

FIG. 4 is a diagram showing the relationship between the speed of the vehicle 1 (vehicle speed), the depression amount of the accelerator pedal (accelerator opening), and the gear position. As shown in FIG. 4, the gear is set to a higher gear as the speed of the vehicle 1 increases. In addition, the gear is set to a lower gear as the accelerator pedal depression amount increases.

For example, the speed of the vehicle 1 and the depression amount of the accelerator pedal change from the value indicated by s1 in FIG. 4 to the value indicated by s2 in FIG. 4 while the accelerator pedal depression amount is maintained constant. Consider the case. Here, since s1 is in the area where the gear is set to the second speed and s2 is in the area where the gear is set to the third speed, in this case, the gear of the automatic transmission 3 is the second speed. To 3rd speed.

On the other hand, the speed of the vehicle 1 and the depression amount of the accelerator pedal change from the values shown in s3 in FIG. 4 to the values shown in s4 in FIG. Consider the case. Here, since s3 is in the range where the gear is set to the third speed and s4 is in the range where the gear is set to the second speed, in this case, the gear of the automatic transmission 3 is the second speed. To 3rd speed.

The output torque control unit 65 controls the output torque of the internal combustion engine 2. The output torque control unit 65 basically controls the output torque based on the depression amount of the accelerator pedal detected by the accelerator sensor 41. The output torque control section 65 basically outputs the output torque of the internal combustion engine 2 so that the output torque of the internal combustion engine 2 is kept constant when the depression amount is kept constant when the gear stages of the automatic transmission 3 are the same. To control. On the other hand, the output torque control unit 65 changes the output torque of the internal combustion engine 2 so that the output torque of the internal combustion engine 2 increases when the depression amount increases, and the output torque of the internal combustion engine 2 decreases when the depression amount decreases. The output torque is controlled to be small.

<<Frequency change frequency>>
By the way, when the vehicle 1 is traveling on a road having a varying slope, the speed of the vehicle 1 may change in accordance with the change in the gradient, and the gear speed may frequently change accordingly. This will be described with reference to FIG.

FIG. 5 is a time chart showing changes in vehicle speed and gear speeds when the vehicle 1 is traveling on a road having a varying gradient. In the example shown in FIG. 5, the amount of depression of the accelerator pedal is constant, for example, in the fully opened state.

As shown in FIG. 5, the vehicle 1 is traveling on a road having a large slope between times t0 and t2. Therefore, the speed of the vehicle 1 is low, and therefore the gear is set to the second gear, which is a low gear, based on the map shown in FIG. After that, the vehicle 1 is traveling on a road with a small slope (including a down slope) between times t2 and t4. Therefore, the speed of the vehicle 1 is high, and therefore the gear is set to the third gear which is a high gear based on the map shown in FIG.

After that, the vehicle 1 travels on a road having a large slope from time t4 to t6, and travels on a road having a small slope from time t6 to t8. As a result, the gear stage of the automatic transmission 3 is set to the second speed during the times t4 to t6 and the third speed during the times t6 to t8. When the road having a large slope and the road having a small slope are alternately driven in this way, the automatic transmission 3 frequently repeats shift up and shift down, resulting in deterioration of drivability. Invite.

On the other hand, if the shift of the automatic transmission 3 is restricted in order to suppress frequent up-shifting and down-shifting of the automatic transmission 3, the speed and acceleration of the vehicle 1 will be so high as to make passengers of the vehicle 1 feel uncomfortable. It will change. As a result, passenger comfort is lost.

<<Control of gear stage>>
Therefore, in the present embodiment, the shift control unit 64 causes the future change estimation unit 63 to estimate the future change speed of the vehicle acceleration at the maximum driving force as a reference change speed range in which the passenger does not notice the change in acceleration. When it is inside, it is configured to prohibit the change of the gear position. In addition, the shift control unit 64 permits the change of the gear speed when the future change speed of the acceleration of the vehicle at the maximum driving force estimated by the future change estimating unit 63 is outside the reference change speed range. Composed.

Here, as a result of the study by the inventors of the present application, the occupant of the vehicle 1 has an acceleration not when the acceleration of the vehicle 1 is constant but when the acceleration of the vehicle 1 is changing according to a certain law. The inventors of the present application have found that it feels constant. Furthermore, when the acceleration of the vehicle 1 has a relationship represented by the following expression (3), the inventors of the present application will recognize that the occupant of the vehicle 1 is accelerating (or decelerating) the vehicle 1 at a constant acceleration. I found that I felt.
a(t)=α·exp(−β·v(t)) (3)
In Expression (3), a(t) is the acceleration of the vehicle 1 at time t, and v(t) is the speed of the vehicle 1 at time t. Further, α and β are constants.

Here, by substituting a(t)=dv(t)/dt for rearranging, the equation (3) can be expressed as the following equation (4). If both sides of the following equation (4) are integrated and arranged, the equation (4) can be expressed as the following equation (5).

Here, assuming that the speed v(t)=0 of the vehicle 1 at time t=0, α·β·t ₀ =1 is established, so that the equation (5) can be expressed as the following equation (6). .. Further, when both sides of the equation (6) are differentiated, the equation (7) is derived, and when both sides of the equation (7) are further differentiated, the equation (8) is derived. Note that J(t) in Expression (8) represents jerk. Then, the equation (9) is derived from the equations (7) and (8).

As described above, the expression (3) represents the relationship between the speed and the acceleration that the occupant of the vehicle 1 feels to be accelerating (or decelerating) with uniform acceleration. The relationship between the jerk and the acceleration at which one passenger feels that the passenger is accelerating (or decelerating) at uniform acceleration is shown. Therefore, when the current acceleration is a(t), the occupant of the vehicle 1 feels that the acceleration has not changed when the acceleration changes at the acceleration change rate (jerk) represented by the equation (9). become.

Further, the inventors of the present application find that the jerk of the vehicle 1 is within a certain range (hereinafter, referred to as “reference change speed range”) centered on the jerk J(t) calculated by the above equation (9). At times, it has been found that the passengers of the vehicle 1 do not notice the change in acceleration. Specifically, the reference change speed range is represented by the following formula (10), for example.
−β·a(t) ² −P≦J(t)≦−β·a(t) ² +P (10)
In Expression (10), P is a positive constant and is experimentally obtained. Since there are individual differences in the range in which the passengers do not notice the change in the acceleration of the vehicle 1, P is set to a value that many passengers do not notice.

Here, as described above, the future change estimation unit 63 estimates the future change in the acceleration a of the vehicle 1 at the maximum driving force. Therefore, the future change estimation unit 63 estimates the transition of the acceleration a of the vehicle 1 from the present time to a predetermined time later (for example, 10 seconds later), and also estimates the transition of the jerk J from the transition of the acceleration a.

The shift control unit 64 determines whether or not the jerk J estimated by the future change estimation unit 63 at each time point from the present time to a predetermined time later is within the reference change speed range represented by the above equation (10). .. Then, when the jerk J at each time point is within the reference change speed range, the shift control unit 64 does not notice the change in acceleration. Therefore, referring to the map shown in FIG. The gear is maintained even when it is time to shift.

On the other hand, when the jerk J at each time point is out of the reference change speed range, the shift control unit 64 permits the change of the gear stage because the acceleration changes enough to be noticed by the passenger unless the gear is changed. Therefore, when the jerk J may fall outside the standard change speed range from the present time to the predetermined time, the speed is changed according to the map shown in FIG. As a result, the gear is shifted to an appropriate gear, so that the change in the acceleration of the vehicle 1 falls within the reference change speed range. Therefore, when the jerk J at each time point is outside the reference change speed range, the shift control unit 64 changes the gear step so that the change speed of acceleration of the future vehicle falls within the reference change speed range. Can be said.

FIG. 6 is a time chart showing changes in vehicle speed, jerk, and gear speeds when the vehicle 1 is traveling on a road having a varying slope. In particular, FIG. 6 shows a transition when the vehicle 1 is traveling on a road having the same gradient change as the example shown in FIG.

The upper broken line X in the jerk of FIG. 6 indicates −β·a(t) ² +P, and the lower broken line Y indicates −β·a(t) ² −P. Therefore, the area sandwiched between the upper and lower broken lines indicates the reference change speed range. In the example shown in FIG. 6, it is expected that the jerk is maintained within the reference change speed range over the period from time t0 to time t11. As a result, in the example shown in FIG. 6, even though the vehicle speed of the vehicle 1 changes in the same manner as in the example shown in FIG. 5, the gear position of the automatic transmission 3 remains at the third speed. Become.

<<Specific control>>
FIG. 7 is a flowchart showing a shift determination process for determining whether or not a shift should be performed. The illustrated control routine is executed at regular time intervals.

First, in step S11, the gradient acquisition unit 61 acquires the gradient of the road on which the vehicle 1 will travel in the future. Specifically, the gradient acquisition unit 61 identifies a road on which the vehicle 1 is scheduled to travel in the future, based on the preset traveling route of the vehicle 1 and the current position information transmitted by the GPS receiver 52. In addition, the gradient acquisition unit 61 acquires the gradient on the road scheduled to travel in the future from map information and the like.

Next, in step S12, the driving force calculation unit 62 calculates the maximum driving force of the vehicle 1. The maximum driving force of the vehicle 1 is calculated based on information on the current gear stage of the automatic transmission 3 (for example, a command value to the automatic transmission 3).

Next, in step S13, the future change estimation unit 63 causes the future vehicle speed v(t) and acceleration a(t) of the vehicle 1 when the driving force of the vehicle 1 is maintained at the maximum driving force at the current gear position. And estimate future changes in jerk J(t). Specifically, the acceleration at each time t is calculated based on the above equation (2), and the speed v at each time t is calculated based on the calculated acceleration a(t) and the current speed v(t). (T) is calculated. Further, the jerk J(t) at each time t is calculated by obtaining the time change of the acceleration calculated in this way.

Next, in step S14, the shift control unit 64 determines that the accelerator pedal depression amount is constant based on the future speed v(t) estimated by the future change estimation unit 63 in step S13 and the map shown in FIG. If it is maintained as it is, it is determined whether or not shifting is expected. For example, when the future speed v estimated by the future change estimation unit 63 changes from the speed of S3 in FIG. 4 to the speed of S4, it is determined that a shift is expected. If it is determined in step S14 that shifting is not expected, the control routine is ended. On the other hand, if it is determined in step S14 that gear shifting is expected, the control routine proceeds to step S15.

In step S15, it is determined whether or not the future jerk J(t) estimated by the future change estimation unit 63 in step S13 is within the reference change speed range shown by the above equation (10). When it is determined in step S15 that the future jerk J(t) is within the reference change speed range, the control routine proceeds to step S16. In step S16, gear shifting in the automatic transmission 3 is prohibited, and the control routine is ended.

On the other hand, if it is determined in step S15 that the future jerk J(t) is outside the reference change speed range, the control routine proceeds to step S17. In step S17, gear shifting in the automatic transmission 3 is permitted. Therefore, when the speed of the vehicle 1 changes so as to cross the boundary line between the gear stages in FIG. 4, the automatic transmission 3 shifts.

<<Effect>>
According to the present embodiment, the shift of the automatic transmission 3 is prohibited when the passenger is expected not to notice the change in acceleration. For this reason, even when the vehicle is traveling on a road where the gradient changes so that upshifting and downshifting are frequently repeated in a stepped automatic transmission, the occupant may not notice the change in acceleration. If it is not expected, shifting is prohibited. As a result, deterioration of drivability due to frequent shifts is suppressed while maintaining passenger comfort.

≪Modification≫
In the above-described embodiment, the shift control unit 64 determines whether or not the gear shift is possible based on whether or not the occupant does not notice the change in the acceleration of the vehicle 1. However, the shift control unit 64 may determine whether or not the shift can be performed based on whether or not the passenger is unaware of the change in the speed of the vehicle 1. In this case, the future change estimation unit 63 changes the future vehicle speed at the maximum driving force based on the road gradient acquired by the gradient acquisition unit 61 and the maximum driving force calculated by the driving force calculation unit 62. To estimate. In addition, in this case, the shift control unit 64 determines that the future speed change speed of the vehicle at the maximum driving force estimated by the future change estimation unit 63 is within the reference change speed range in which the passenger does not notice the speed change. Is prohibited, the change speed of the future vehicle at the maximum driving force estimated by the future change estimating unit 63 is outside the reference change speed range, and the change of the gear speed is permitted. To do.

<Second embodiment>
Next, a control device according to the second embodiment will be described with reference to FIG. Below, it demonstrates focusing on a different part from the control apparatus which concerns on 1st embodiment.

By the way, as described above, the occupant of the vehicle 1 feels that the acceleration is constant when the acceleration changes so as to become the acceleration shown in the above-described equation (3). On the other hand, when the depression amount of the accelerator pedal is maintained constant, the driver expects the vehicle 1 to accelerate (or decelerate) at a constant acceleration. Therefore, when the depression amount of the accelerator pedal is kept constant, it is preferable that the vehicle 1 accelerates (or decelerates) at the acceleration shown in the equation (3).

However, on a road where the gradient changes continuously and gradually, the actual acceleration of the vehicle 1 also changes as the gradient changes. As a result, the acceleration of the vehicle 1 changes faster or slower than the acceleration shown in the equation (3) even if the accelerator pedal depression amount is kept constant.

Therefore, in the present embodiment, the driving force calculation unit 62 also calculates the current driving force when the gear stage of the automatic transmission 3 is the current gear stage and the output torque of the internal combustion engine 2 is the current output torque. Is configured as follows. In addition, the future change estimation unit 63, based on the road gradient acquired by the gradient acquisition unit 61 and the current driving force calculated by the driving force calculation unit 62, assumes a future when the current driving force is assumed to continue. Is also configured to estimate the change in the acceleration of the vehicle 1. Then, the output torque control unit 65 is outside the minimum change speed range in which the change speed of the future acceleration of the vehicle 1 when the current drive force estimated by the future change estimation unit 63 is assumed to continue is narrower than the reference change speed range. When, the output torque is controlled so that the changing speed falls within the minimum changing speed range.

Hereinafter, control of the output torque in the output torque control unit 65 will be described in detail. As described above, when the jerk of the vehicle 1 has the relationship represented by the above formula (9), the passenger of the vehicle 1 feels that the vehicle 1 is accelerating (or decelerating) at a constant acceleration. Become. Therefore, if the jerk of the vehicle 1 is maintained near the value calculated by the above equation (9), the occupant of the vehicle 1 will feel that the vehicle 1 is accelerating (or decelerating) at a constant acceleration.

Therefore, in the present embodiment, the output torque control section 65 determines that the jerk of the vehicle 1 is the jerk J(t) calculated by the above equation (9) when the depression amount of the accelerator pedal is kept constant. The output torque of the vehicle 1 is controlled so that the output torque is maintained within a constant range (hereinafter, referred to as a minimum change speed range) centered on the. Here, the minimum change speed range is narrower than the reference change speed range in the above-described first embodiment.

Specifically, based on the road gradient acquired by the gradient acquisition unit 61 by the future change estimation unit 63 and the current driving force calculated by the driving force calculation unit 62, when the current driving force continues A future change in the acceleration a′ of the vehicle 1 is estimated. The acceleration a′ of the vehicle 1 at time t is calculated, for example, by the following equation (11).
a′=[Fdc−F(A·v ² +B·v+C)−M·g·sin θ]/M (11)
In the formula (11), Fdc represents the driving force currently output by the vehicle 1, that is, the driving force when the accelerator pedal is currently depressed, and the current driving force calculated by the driving force calculation unit 62 is calculated. The quantity is substituted.

Further, the future change estimation unit 63 of the present embodiment repeats the calculation of the speed and the acceleration of the vehicle 1 after a minute time Δt seconds, similarly to the first embodiment, so that the vehicle 1 from the present time to a predetermined time later. Estimate the change in acceleration. In addition, the future change estimation unit 63 estimates the change in the jerk J′ when it is assumed that the current driving force continues, from the calculated change in the acceleration a.

The output torque control unit 65 determines that the jerk of the vehicle 1 at each time point from the present time to a predetermined time period after the current driving force estimated by the future change estimation unit 63 continues is given by the following formula (12). It is determined whether or not it is within the minimum change speed range.
−β·a′(t) ² −Q≦J′(t)≦−β·a′(t) ² +Q (12)
In Expression (12), Q is a positive constant and is experimentally obtained. However, Q is set to a value smaller than the constant P in the above equation (10).

Then, when the output torque control unit 65 determines that the jerk of the vehicle 1 at each time point from the present time to the predetermined time period is within the minimum change speed range represented by the above formula (12), the internal combustion engine The output torque of 2 is maintained unchanged. On the other hand, when the output torque control unit 65 determines that at least a part of the jerk of the vehicle 1 at each time point from the present time to the predetermined time period is out of the minimum change speed range represented by the following formula (12). Changes the output torque of the internal combustion engine 2 even if the accelerator pedal depression amount is constant. For example, when the jerk of the vehicle 1 is smaller than the minimum change speed range, the output torque control unit 65 changes the output torque of the internal combustion engine 2 to be large. On the other hand, when the jerk of the vehicle 1 is larger than the minimum change speed range, the output torque control unit 65 changes the output torque of the internal combustion engine 2 to be small.

FIG. 8 is a flowchart showing a shift determination process for determining whether or not a shift should be performed. The illustrated control routine is executed at regular time intervals. Note that steps S21 to S27 in FIG. 8 are the same as steps S11 to S17 in FIG.

When it is determined in step S25 that the future jerk J(t) is within the reference change speed range, the control routine proceeds to step S26, and the shift of the automatic transmission 3 is prohibited. Next, in step S28, it is determined whether or not the future jerk J'(t), assuming that the current driving force continues, is within the minimum change speed range shown in the above equation (12). If it is determined in step S28 that the future jerk J'(t) is within the minimum change speed range, the control routine is ended without adjusting the output torque. On the other hand, if it is determined in step S28 that the future jerk J'(t) is outside the minimum change speed range in step S28, the process proceeds to step S29. In step S29, the output torque of the internal combustion engine 2 is adjusted even if the depression amount of the accelerator pedal is constant.

According to the second embodiment, as long as the accelerator pedal depression amount is constant, the change in the acceleration of the vehicle 1 is maintained in the vicinity of the range where the passenger feels that the acceleration is constant. Therefore, the passenger is prevented from feeling frequent acceleration/deceleration, and the comfort of the passenger is improved.

≪Modification≫
In the second embodiment described above, the output torque control unit 65 controls the output torque so that the passenger feels that the acceleration of the vehicle 1 is constant. However, the output torque control unit 65 may control the output torque so that the passenger feels that the speed of the vehicle 1 is constant. In this case, the future change estimation unit 63, based on the gradient of the road acquired by the gradient acquisition unit 61 and the current driving force calculated by the driving force calculation unit 62, assumes that the current driving force will continue in the future. Is also configured to estimate the change in the speed of the vehicle 1. In addition, in this case, the output torque control unit 65 determines that the change speed of the future vehicle speed when the current drive force estimated by the future change estimation unit 63 is assumed to continue is the minimum change that is narrower than the reference change speed range. When the speed is outside the speed range, the output torque is controlled so that the speed of change falls within the minimum speed change range.

1 vehicle 2 internal combustion engine 3 automatic transmission 10 control device 11 electronic control unit (ECU)
41 accelerator sensor 42 vehicle speed sensor 43 torque sensor 44 weight sensor 51 vehicle exterior communication device 52 GPS receiver

Claims (3)

A control device for a vehicle having a stepped automatic transmission,
A slope acquisition unit that acquires the slope of the road on which the vehicle will travel in the future;
A driving force calculation unit that calculates a maximum driving force when the gear stage of the automatic transmission is the current gear stage,
Based on the maximum driving force calculated by the gradient and the driving force calculation unit of the road acquired by the gradient acquisition unit, a future change estimation unit that estimates a change in the speed or acceleration of the future vehicle at the time of maximum driving force,
A shift control unit for controlling the gear stage of the automatic transmission,
The shift control unit is configured such that a future vehicle speed or acceleration change speed at the maximum driving force estimated by the future change estimation unit is within a reference change speed range in which a passenger does not notice a change in speed or acceleration. At this time, the change of the gear is prohibited, and when the change speed of the future vehicle speed or acceleration at the maximum driving force estimated by the future change estimating unit is outside the reference change speed range, A vehicle controller that permits changes. Further comprising an output torque control unit for controlling the output torque of the internal combustion engine,
The driving force calculation unit also calculates the current driving force when the gear stage of the automatic transmission is the current gear stage and the output torque of the internal combustion engine is the current output torque,
The future change estimation unit, based on the road gradient acquired by the slope acquisition unit and the current driving force calculated by the driving force calculation unit, the future vehicle when it is assumed that the current driving force has continued. Estimate changes in speed or acceleration,
The output torque control unit is outside the minimum change speed range in which the change speed of the future vehicle speed or acceleration when it is assumed that the current driving force estimated by the future change estimation unit continues is narrower than the reference change speed range. The control device for a vehicle according to claim 1, wherein the output torque is controlled so that the changing speed falls within the minimum changing speed range. Further comprising a communication device capable of communicating with another vehicle different from the vehicle,
The vehicle control device according to claim 1, wherein the gradient acquisition unit acquires, via the communication device, a gradient of a road on which the vehicle is scheduled to travel in the future, from another vehicle traveling in front of the vehicle. ..